1. Field of the Invention
The present invention relates to a reeling machine designed for continuous winding of a fibrous web, and more particularly for continuous winding of a paper or carton web.
2. Description of the Related Art
Reeling machines such as disclosed in European patent document EP 0 483 092 B1 or PCT document WO 98/52858 A1 (PR10706 WO), are used in machines designed for the manufacture or conversion of fibrous webs such as, paper or carton.
In today""s modern winding designs, preparing to change a reel spool requires the spool with the virtually fully-wound jumbo roll (xe2x80x9cwound rollxe2x80x9d) to be brought into a final position (reel spool changing position), in which there is no longer any active contact (the so-called xe2x80x9cnipxe2x80x9d) between a reel drum and the jumbo roll. At this moment where there is no longer any nip, appropriate measures have to be employed to ensure that no air becomes trapped between the individual layers of the virtually fully-wound roll. It is also important to maintain the xe2x80x9cwound-inxe2x80x9d web tension so as to guarantee the desired winding quality even in the outer area of the roll. The problems inherent in this become more complex as the operating speed of the reeling machine increases (scale of 1500-2500 m/min) and where wound rolls with greater manufactured diameters are employed (scale of 2.5-4.5 m).
An attempt to solve this problem has already been made in a reeling machine of the type described above, as is manifest to the applicant from Unexamined German Patent Application DE 44 01 804 A1 (PR10035 DE). This document describes an arrangement comprising a rider roll with an elastic cover, which can be pressed against a jumbo roll separated from a reel drum by means of a pneumatic drive apparatus. The purpose of this arrangement is to limit the build up of trapped air between the individual layers of the jumbo roll and to maintain the xe2x80x9cwound-inxe2x80x9d web tension during a reel spool change. However, the rider roll suffers from a significant drawback in that it is subject to deflection due to its own weight, that the roll deviates from an ideal cylinder shape to a greater or lesser extent over the entire width due, for example, to varying paper thickness, and that the rider roll cannot therefore operate evenly over the whole width of the web on the surface contours of the virtually fully-wound jumbo roll. In consequence, it is impossible to completely avoid air being trapped between the outer layers of the virtually fully-wound roll. A further rider roll is known from German Patent Application DE 91 17 272 U1 in which the roll described also suffers from the same drawback mentioned above.
European patent document EP 0 714 373 (=WO 95/34495 A1) describes a process and an arrangement for depositing final web layers on a jumbo roll generated during the winding process in a reeling machine. In this process, an air squeeze arrangement is brought into active contact with the surface of the jumbo roll before the final web layers are deposited, whereupon the jumbo roll is moved into its change position whilst this active contact is maintained, thus enabling the desired strength of active contact to be retained for the purpose of avoiding the trapping of air between the individual layers of the roll. The element in the air squeeze arrangement, which presses onto the jumbo roll, is a pressing brush. Previous experiments have shown that the use of a brush can be disadvantageous in that a constant danger exists that the hairs of the brush will damage sensitive types of paper. Also, individual brush hairs may become detached and enter into the paper cycle as spurious components or brush hairs themselves may be damaged.
Furthermore, certain reeling machines are known in which there is no contact between the reel drum and the jumbo roll after each reel spool change, for the remainder of the winding process. In this arrangement an air squeeze apparatus, including an appropriate air squeeze element, is provided in the form of a rider roll operating continuously on the jumbo roll. A reeling machine of this type is known, for example, from German Patent Applications G 88 08 823.5 (=U.S. Pat. No. 5,249,758) and DE 298 11 053.
Both German Patent Applications cited above suffer from the drawback that a danger of deflection exists in broader paper or carton machines. The construction of the apparatus in accordance with cited document DE 298 11 053 U1 is both costly and complicated since it must be possible to position the point of support of the rider roll on the web, in the direction of winding, by a definable angle to the point where the web is wound on, while simultaneously maintaining a definable xe2x80x9cpressing forcexe2x80x9d on the web that is spooled onto the reel spool.
The present invention provides an improved reeling machine in which the problem of trapped air between the individual layers of the jumbo roll, is avoided, thereby ensuring that the xe2x80x9cwound-inxe2x80x9d web tension is maintained and that sideways displacement of the individual layers of the jumbo roll is prevented.
In one embodiment of this invention a reeling machine is configured such that the air squeeze arrangement is composed of a positionable supporting profile with segmented rolls positioned next to each other by means of bearings. A tube surrounded by a guide pipe and filled with a pressure medium from at least one pressure source is provided in the interior of the supporting profile, and the non-rotating bearing bushings of the bearings are centrally supported on this tube by at least one power transmission element. This arrangement is advantageous in that any potential unevenness in the surface contours of the virtually fully-spooled jumbo roll can be countered by radial adjustment of the individual segmented rolls together with associated pressure compensation in the tube, thereby ensuring that no air is trapped between the individual layers of the jumbo roll while simultaneously maintaining the xe2x80x9cwound-inxe2x80x9d web tension. In addition, the technical construction of the air squeeze arrangement according to the invention produces a system, which is largely self-cushioning, and which reduces, to the greatest extent possible, any vibration induced by the web or the wound roll.
For reasons stemming from the demands of both printing technology and structural and manufacturing technology, the supporting profile mounted between the round bearing bushings of the bearings is composed of a supporting pipe, preferably a round supporting pipe.
The power transmission element may be a plunger, since it fulfils all requirements concerning functionality, serviceable life and is simple to produce in terms of the manufacturing technology required.
The pressure medium is a fluid, preferably a hydraulic fluid, or a gas. Both pressure media conform to state-of-the-art technology and both represent a cost-effective pressure medium suitable for a variety of operating conditions.
With regard to the air squeeze arrangement, it is advantageous for the segmented roll to have a diameter of between 200 and 400 mm, preferably between 250 and 350 mm, and a width of between 150 and 400 mm, preferably between 200 and 300 mm. These dimensions serve to ensure that the air squeeze arrangement does not subject the fibrous web to any kind of damage, such as grooving or other types of marking, or changes in its properties, such as shiners (shiny spots). With regard to avoiding the kinds of damage and changes in properties mentioned above, the arrangement may also include at least two segmented rolls placed directly next to each other at a distance of between 0.5 and 5 mm, preferably of between 1.0 and 2.0 mm.
Furthermore, for the purpose of avoiding the build-up of air in front of the air squeeze arrangement, it is advantageous for the segmented roll to have a rubberized and/or grooved surface. A rubberized surface of the segmented rolls should, by preference, have a hardness of between 50 and 200 PandJ (Pussy and Jones), ideally between 80 and 120 PandJ (Pussy and Jones).
To allow scope for rapid and marginal adjustment of the air squeeze arrangement the supporting profile is positioned eccentrically. The eccentric structure preferably features an eccentricity of between 2 and 20 mm, ideally between 5 and 12 mm, since this eccentricity can be achieved without any major additional structural complexity.
In order to avoid the emergence of trapped air between the individual layers of the jumbo roll, the air squeeze arrangement can be positioned against the jumbo roll at the point where the fibrous web meets the surface shell of the jumbo roll. Points before or after this contact point lead to reduced effectiveness with regard to the avoidance of trapped air.
In another embodiment of the invention the air squeeze arrangement is positioned against the jumbo roll in front of the opening of the nip between the reel drum and the jumbo roll, since the air squeeze arrangement can achieve the greatest possible efficiency in its action only when the nip is open.
The air squeeze arrangement is generally to be positioned in a linear fashion, preferably horizontally and/or vertically, and/or generally along the contour of a segment of a circle. These various application positions and movements offer practical advantages in terms of moving mass or changes in mass, as well as in terms of how they are regulated.
In a further embodiment of the invention an active area is formed between the jumbo roll and the air squeeze arrangement, the effective force applied in the active area can be adjusted through displacement of the air squeeze arrangement. This enables the achievement of a good winding result even for the last layers wound onto the roll. The jumbo roll is formed with a defined, evenly-wound tightness throughout the entire duration of the winding process, since the effective force in the active area between the jumbo roll and the air squeeze arrangement can be finely adjusted, even in the final phase of winding where there is no longer a nip between the Pope cylinder and the jumbo roll.
The specifications of the invention mentioned above are applicable not only in the various combinations given here, but also in other combinations or in isolation, without exceeding the scope of the invention.